Armus started out as an NYPD detective. He began his television career, when Telly Savalas picked him to become the technical advisor for Kojak (photographed by Jerry Finnerman and Charles Correll). He also wrote scripts for the series, and acted in two episodes. Armus has also written for such television shows as CHiPs, Police Woman, Streets of San Francisco, Bronk, and The Fall Guy. He served as producer as well as a writer for Streethawk and then the 1980s series Airwolf in 1984 and became a producer on Knight Rider for the 1985-86 season. During his tenure, Winrich Kolbe and Robert Bralver both directed episodes of the latter show. Most notably, however, Armus was the co-producer for the hit series NYPD Blue, and as such shared a 1994 Emmy nomination with the show's production team when it was nominated for Outstanding Drama Series. Armus and the NYPD Blue production team were nominated again the following year, this time winning the award. Armus himself also received an Emmy nomination in 1994 for co-writing the NYPD Blue episode "Personal Foul". He also received the Humanitas Prize in 1994 for 60 Minute Category for NYPD Blue.